Cyanamide oven



sept. 1s, 192s.

' G. E. COXl CYANAMIDE OVEN Filed June 17, 1925 GEORGE E COX' IN VEN TOR.

-. ATTORNEY.

\ Patented sept. is, 1928.

UNITED STATES PATENT OFFICE.

GEORGEE. COX, OF NIAGARA FALLS, NEW YORK, ASSIGNOR T AMERICAN CYANA- MID COMPANY, OF NEW YORK, N. VY., .A CORPORATION OF MAINE.

UYANAMIDE ovEN.

Application led J'une 17, 1925. Serial No. 37,695.

This invention relates to a method of and means for manufacturing calcium cyanamide or lime nitrogen by the reaction between calcium carbide and nitrogen. It has been found in the well-known process of nitrogen fixation by the cyanamide reaction, that the efficiency is greatly increased by an increase in the size of the ovens used, whereby better control of the various factors involved is obtained, and the operating costs are decreased. At the completion of the fixation,- the calcium cyanamide is in the form of a block or pig which must be removed from the oven and taken to the point of fur- 15. ther treatment. When the pig weighs only `a few hundred pounds this is a relatively simple matter but when the pig weighs several tons, difficulties arise. A modern oven may produce a pig about four feet in diameter and six and one-half feet-high. weighing say four tons, and the pig must be raised to a point above the oven, say to a height of seven or eight feet, to clearthe same. In order to facilitate' this, it has been customary to embed steel rods formed with eyes projecting up above the surface of the subsequently formed pig and providing means for attaching thereto hooks or other devices, whereby the pig of calcium cyanamide was raised up out of the oven.`

, This was satisfactory in that it provided means for removing the pig, but in practice several difficulties were encountered. The rods, of necessity,*were made of heavy stock which'was bent at one end to form an eye and at the other end to form an anchorage in the pig. Because of the heavy material it was necessary to forge each piece by hand making the same rather expensive. The nitrification of the calcium carbide in the oven takes place at a relatively high tempera- 'ture and the steel rods react with nitrogen.

becomingweak and brittle. As a result after a rod has been used a short time it becomes so weakened that the weight of the pig lbeing` lifted from the oven is often suiiicient to cause it to give way, allowing the pig to fall and break. This not only a loss of valuable material but considerable danger of injury to the workman exists. The cost of replacements of rods is, therefore, rather high.

The present invention is intended to ob in the calcium carbide, before nitrifying,'

viate the diiiiculties inherent in the removal of pigs-from cyanamide ovens, it being among the objects thereof to provide an oven construction whichwill allow of theready removalof pigs therefrom, at the same time minimizing the danger of breaking the pigs and injuring the workmen.

AIt is a further object of this invention to provide a method of manipulating the parts are made in the base portion which is lined with refractory material as usual and is formed withmeans, at the upper end, for the reception ofthe upper portion of the oven, which is also lined with refractory material,

.and forming a gas-tight joint therewith. lA

cover fits over the top of the upper portion and serves to completely enclose the oven when in operation.

The interior of the upper portion is tapered outwardly from the top to the junction with the base portion, and the hase portion is tapered outwardly from the bottom to the said junction. As a result the pigs formed therein have a larger diameter at trie -central portionV than at the ends, being somewhat barrel-shaped. In order to lremove the pig, the cover is first lifted off and then the upper portion of the oven is removed. or both may be removed simultaneously. The pig is then gripped by a device, operated by a traveling crane, and the pig is raised by the raising of the device. Because of its :construction, which is similar in4 principle to the well-known ice tongs, the weight of the pig increases the pressure of the device and causes it to grip the pig tighter, instead of constituting a straintending to oppose the effect of the gripping device, as in the means previously used, and it practically eliminates the danger of the pig breaking away from the lifting apparatus.

In the accompanying drawing, constitutasl Fig. 2 is a cross-sectional View thereof taken along the line II-II of Fig. 1.

The oven consists essentially of a circular sheet metal base l having integrally formed side Walls 2 and lined both along the sides and bottom with suitable heat insulating material 3, such as sil-o-cel, and an inner lining 4 of refractory material, such as fire brick, or the like, is formed along the walls 2 within the heat insulating lining 3. Atthe junction between the base and the side walls, a row of refractory brick 5, of special form to make a rounded corner is provided and a row of sector shaped refractory bricks 6, having tapered openings 7 therein, covers the major portion of the base of the oven. The openings 7 are tapered outwardly from the intey rior of the oven proper down to ducts 8, which are connected to a source of suitable gas, such as nitrogen entering through the side walls. A central opening 9 is provided in the refractory linings of the base and provides a receptacle for the lower end of the electrode `used in the oven.

At the upper end of the side walls 2 are secured a series of sector-shaped angle members 10, having projections 11 at. the upper surface thereof, the members being joined to gether to form a complete circle around the upper edge o-f the side walls 2. S-shaped double angle members 12 are, in a similar manner, joined together to form a ring, being welded Aor otherwise secured to the angle members 10. The members 12 are adapted to cooperate with angle members 13, secured to the wall or shell 14 of the upper portion of the oven, and having a depending projection formed thereon. A sand seal 15 provides an air tight joint between the two portions of the oven. Thel upper portion 14 is lined with heat insulating material 16 and refractory material 17 similar to the materials used in the lower portion of the oven. Generally the height of the upper portion 14; is about twice the height of the lower portion 2 of the oven. Along the ltop edge of portion 14 is secured a series of angle and S-shaped members 18,

similar to those on the upper part of the lower portion 2 of the oven, cooperating with downwardly projecting portions 19, of cover 20, asand seal 21 being formed at the junction. Eyes 22, are welded or otherwise attached to the top of the shell 14, providing means for raising the same from the base of the oven.

The cover 20 is filled with heat insulating material A23 and has ears 24 formed thereon for facilitating removal thereof. Anelectrode holder 25 is placed at the center of the cover in alignment with opening 9 and has a terminal 26 electrically connected thereto lined with paper or the like, as is common practice in ovens of this type, and an electrode is placed in .opening 9 and holder 25 passing centrally through the oven. Calcium carbide in finely powderedcondition, is filled intothe oven and the cover 2O is placed thereon. A current is passed' through the electrode to heat the same and nitrogen is caused to tiow through openings S and is distributed, by tapered openings 7 and the crevices between bricks, through the carbide in the oven. Nitrification takes place, resulting in a solid block or pig of calcium cyanamide.

In order to remove the same, a crane is attached to eyes 22 of shell 1/1 and the upper portion of the ovenl is lifted od. In order to facilitate the removal thereof, and also the removal of the pig from the oven, the inner side Walls 4 and 17 of the lower and upper portions of the oven, respectively, are tapered outwardly to the junction between the two portions. After the removal of shell 14 a gripping device, similarin principle to the well-known ice tongs, is placed over the pig of calcium cyanamide and the tongs lifted by a crane or other device causing the same to firmly and securely grip the pig and'raise the pig from the oven. In this type of device the weight of the pig tends to increase the pressure of the gripping device, thereby minimizing the danger ofthe pig becoming loosened and falling to the ground. i

My invention makes it practical to build of rods embedded in the pigs for lifting the same from the oven, which'rods would be far more expensive for large ovens than for small, for the reason that they must be made of ,heayier stock bv a hand forging method', and

theywould be exposed to the action of hot nitrogen in the oven for a considerably longer time. It is probable that they could only be used once with safety. v

Although I have described my invention setting forth a single embodiment thereof, I am not limited thereto and Iv may make various changes therein within the spirit and scope of my invention. For instance, I may line the parts of the' oven with different materials and in 'some cases may omit the heat insulating linin or substitute a singlelining which will per orm the function of the two described. The construction of the'sand seals may be changed and a different type of seal may be used. Other means for introducing and distributing the nitrogen gas may be provided andthe connections for the electrode may be dierent froln those described.

I have shown an oven in which the upper re-` movable portion 'is of greater height than the lower portion, but this is not `essential as it is apparent that the lower portion may have a greater height. Furthermore, practically the entire wall of the oven may be in the upper portion,'the base 1 having only suflicient wall to provide the necessary sealed joint between the ltwo portions of the oven. These and otherv changesmay1 be made in my invention, the scope of which is defined by the claims appended hereto.

What I claim is:

1. Apparatusfor making a block of calcium cyanamide and other materials which comprises an oven base having a side wall section secured thereto an upper side wall section thereon and a sand seal at the junction of said sections.

'2. Apparatus for making a block of-calcium cyanamide and other materials which comprises an oven base having a side wall section secured thereto an uppery side wall section thereon, and a sand seal at the junction of said sections forming an air tight joint therewith. i

3. Apparatus formaking va block of calcium cyanamide and other materials which comprises an oven base having a side wall section secured thereto an upper-side wall section thereon, the upper side wall section constituting the major part of they height of the oven, and a sand seal at the junction of said sections.

4. Apparatus for making a block ofcalcium cyanamide and other materials which comprisesL an oven base having a side wall section secured thereto, an upper side wall section thereon, a sand sealy at the junction of said sections, and a refractory lining on the inner surface of the oven.

5. Apparatus for making a block of calcium cyanamide and other` materials which comprlses an oven base having a side wall section secured thereto, a removable upper .side wall section thereon, a refractory 1ining on the inner surface of the oven, and heat V insulating material between the lining and the walls of the oven.

6. Apparatus for making a block of calcium cyanamide and other materials which comprises an oven base having a side wall section secured thereto, a removable upper side wall section thereon, a refractory lining on the inner surface of the oven and heat insulating material between the lining and the walls of the oven, the said lining and insulating material of the upper side wall section being removable therewith.

7. Apparatus for making a block ofy calcium cyanamide and other materials which comprises an oven base having a side wall section secured thereto, a removable upper side wall section thereon, a refractory lining on the inner surface of the oven and a plurality of' inlets for nitrogen gas in the lining of the oven base.

8. Apparatus for making a block of calcium cyanamide and other materials which.

comprises a removable oven base havin a side wall section secured thereto, la remova le upper side wall section thereon, a refractory 'lining on the inner surface of the oven and a plurality' of conical inlets for nitrogen gas in the lining of the oven base.

9, Apparatus for making a block of calcium cyanamide and other materials which comprises an 'oven base having aside wall section secured thereto, a removable upper side wall section thereon, a refractory lining on the inner surface of the oven and a plurality of conical inlets for nitrogen 'gas in the lining of the oven base, the small diameter i of said inlets being at the upper surface of said base.

10. Apparatus for making a block of calcium cyanamide and other materials which comprises an oven base having a side wall. section secured thereto, a removable upper sidewall section thereon, a refractor on the inner surface of the oven and, a pluralityV of inlets for nitrogen gas .in the lining of the oven basesubstantially uniformly distributed over'the surface of said base.

In testimony whereof, I have hereunto subscribed my name this 15th day of June, 1925.l

vGEORGE E. cox.

lining 

